The cooling system of most modern vehicles having internal combustion engines is a closed system. It is typical for a gas (such as air and/or coolant vapor) to be caught in the closed coolant system. However, the presence of gas trapped in the coolant reduces cooling system efficiency that may potentially lead to the failure of engine components including the turbo charger and the transmission and may even lead to engine failure itself.
Accordingly, an arrangement is required for aerating the cooling system to allow for the escape of trapped gas. Current de-aeration and degasing systems for internal combustion engine cooling systems incorporates a coolant bottle that has a degasing chamber. A portion of the coolant passes through the degasing chamber during engine operation. The movement of the coolant through the degasing chamber is continuous while the engine is on. As a result, gas is separated from the coolant and is accumulated. The coolant bottle, or degas bottle, also serves as an overflow reservoir for coolant as its temperature rises.
Current degas bottle design is based on the buoyancy effect to separate air from coolant. Air has lower density as compared to engine coolant, thus as the coolant with trapped air moves through a flow path, the air bubbles flow up to the top while the coolant remains below at the bottom of the degas bottle, forming the coolant reservoir. To achieve a good air-coolant separation, the flow path needs to be sufficiently long. However, due to the constraint of vehicle package space, degas bottle size is limited. To achieve a sufficiently long flow path, the degas bottle is internally divided into many small chambers connected by holes, making tooling cost expensive. As coolant flows through the holes, it can become turbulent at a high flow rate. If the turbulence is too severe, the coolant starts foaming and, as a consequence, air bubbles form.
In addition to having known inefficiencies, the degas bottle is in general on the low priority list when vehicle package space is divided and designated. As a result, the degas bottle has to fit into a narrowly defined space. Thus, from vehicle to vehicle, the degas bottle often has to be redesigned to fit within its designated space. As a consequence, the internal chamber and the flow path have to be changed as well, also vehicle to vehicle, resulting in increased design cost.
Accordingly, as in so many areas of vehicle technology, there is room for improvement related to the design of degas bottles used in the cooling system of the modern internal combustion engine.